I've never been in the need of adding/updating/replacing license headers into every source code file in a big project, but now I am. And I always thought there was some popular tool for doing it, because many historical source tarballs have license headers in all their files together with the typical version header applied by the (then popular) RCS/SCCS version control systems.
I mean, just look at big sources published in the 90s by SGI, HP, Berkeley, etc, and it's there. I always thought that was automated, and not only for adding the license notice, but for updating/replacing/removing it.
But I searched and searched, and found no such tool. There are some tools for doing this at GitHub, but they are pretty recent... nothing with a >20-year tradition.
Did all the companies from the commercial UNIX era use their own unpublished in-house shell scripts for doing this? Wasn't there any popular tool for this in those years?